Production of drying oils by hf-hydrocarbon processing



March ll, 1952 R. J. LEE ETAL PRODUCTION OF DRYING OILS BY HF`HYDROCARBON PROCESSING Filed May 4, 1948 c n .i

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Patented Mar. l1, T952 UNITED STATES lPAfir-YINT OFFICE retifin foff Delaware .ing Cornpration. 'texas aGitr, flex la @1TFT Application-MWA, 1948, Seriallblo; :24.958 LA5 Claims. (Cl. 2161071566) This invention relates tothe .productionof i ing oils and other olenic hydrocarbons byfpr'cessing high boiling, non-aromaticVhydrovcarbcns with hydrogen iiuoride and it pertains more par- 2 ,procesvsand operating conditions therefor, which willlfpoducfesuchvdrying oils in large yields while ait th'efs'am'e' time producing valuable icy-product .materials lAnother ,object is to provide a relaticularly to improved methods and means .fffor I5 tivelyslnple'and'inexpensive process for convertobtaining maximum yields of high duality dryiiig oils from dearomatized gas oil and'for'produ'cin'g .and recovering said drying oils with a minimum consumption or loss of hydrogen V,fluoride v(herein referred to as HF).

neutralizing or hydrolyzing certain HF-hydrocarbon complexes produced in hydrocarbon''refining processes wherein HF is employed as the rening or treating agent. Heretoforefsuch not be obtained by commerciauy feasible methds (about .5 to .75 lb. HF was lost per pound lof drying oil produced). An object of thisinvention is to provide a method and means for hydrolyzing HF-hydrocarbon complexes which .n'let'hod will simple distillation and which will therebysubstantally avoid any loss of HFv byaqueous Vdilution or salt formation. Anvimportantv object is to avoid or at least to minimize degradation, cracking, saturation or other undesirable reactions in the recovery step.

Another object is to providea `method forvarying the yield and viscosityof the recovered drying oil. A subsidiary object is to provide a method for increasing the yield ofviscous drying oilwhile f decreasing the yield of low viscosity low molecular weight poly-olen fractions. Another Objectis to produce a nished oil of good color and-high viscosity without requiring further distillation of 40 plish the above objectives without interposing any additional processing steps for recovering the poly-oleiinic oil, and while simultaneously facilitating the recovering of HF.

Another object of the invention is to provide'an ing oils from hydrocarbon charging stocks such for example as ordinary gas oils available in the petroleum industry. A further object is ,toprovide a drying oil of improved characteristicsgwith exceptionally high unsaturation (iodine number) high degree of conjugatiomgood color ad'h'igh blending value as an agent in coating compsitions and/ or for the production of resins, plastics,

and the like. A furtherobiectza o "fwell assbstantially saturated hydrocarbons par- 0 ticljrlybf the motor vfuel boiling range. Other Itis known that drying oils can be. produced by objects will be apparent as the detailed descrip- .tin .fof the invention proceeds.

2inl'piac'ti'cirig' the invention a preferred chargigs'tocli is `a gas' oil which has been dearomatized y ,p15 bytre'atment `with concentrated sulfuric acid. processes have lacked commercial feasibility'be- .Many'charging stock materials such, for example, as olenpolymers, alkylates, and hydrocarbons produced 'by carbon monoxide-hydrogen synthesis may vvcontain no aromatic hydrocarbons and 0 hence "may require no dearomatization step.

-,Relatively pure parainic hydrocarbons such as ',eetaneand'fparafn waxes may be employed but they give ,a less' desirable product distribution and they arefnotas'commercially attractive as the i v "25 yfle'ss valuable gas oils. The dearomatization may enable recovery of substantially anhydrousHF by o cnte'nt'of the charge be substantially eliminated, d* i. e. vthat the Varomatic content should not ma- Nterially exceed about 5% and preferably not more ftlji'an 11%;

treatment of the dearomatized gas oil 5 or other charging stock may be efected at a tem- .xjperature in the range of about 250 to 450 F., 'preferably vabout 300 Vto 350 F. under a pressure ',suiicient to maintainliquid phase conditions and .with altime of contact which mayrange from a Qfew minutes toseveral hours depending upon temperature land intimacy of said contact, excellentresults having been obtained with contact 'T times 'of the order of about 5to 30, e. g. about 20 minutes. yThe `HF-to-oil ratio may vary from 5 I ia'bout-2z1 toabout'zlor more but is preferably in the 'range of about 1:1 to 2:1.

The oducts of the HFA treatment are preferv'ably c led'jand separated into an HF phase lcon- "taining soluble `unsaturated hydrocarbons and an 450 I infsolubleoil phase which consists essentially of improved method and means for producing dry-"" 5; nuns.

TheIlF phase separated from the product of -thetreatingstep is vsubjected to a partial stripplngfop'eration jundercarefully controlled condii, tions "Ato Vremove most of the HF from an VHF `plexi'withoutdecomposing or degrading said bonds.

' range from about 400 to 3 complex. This can usually be accomplished at temperatures below about 250 and in most cases at temperatures in the range of about-.100 to 200 F.; it may be accomplished by the use of an inert stripping gas or by heating. It is important that at least one and preferably one and one-half to two mols of HF should be left in the stripped residue for each mol of double bonds present therein; for practical purposes this means that the stripped residue should contain at least about 30% HF and preferably about 35 to 50% pressed herein represents an average of one ethylenic linkage per molecule of oil. By this terminology, therefore, one mol of a polyolenc oil containing four ethylenic linkages per molecule would be equivalent to four mols of double In other Words, the stripping must leave about 1 to 2 molecules of HF per double bond in the hydrocarbon component of the hydrogen iiuoride-hydrocarbon complex. If attempts are made to recover all of the HF by stripping or distillation, even at 10D-125 F., the residue oil is degraded to dark tarry products of low degree of unsaturation.

The stripped complex which contains at least about 1 to 2 molecules of HF per double bond in the hydrocarbon component (i. e. the hydrocarbon product finally produced) is then hydrolyzed with an'aqueous HF solution containing about 1 part to 3 parts of HF weight to 2 parts of Water. The HF component of the hydrolyzing mixture does not interfere with effective hydrolysis and in fact appears to exert a benecial effect in absorbing heat of hydrolysis. that the aqueous HF is not employed in this case simply to remove free HF from a simple solution thereof, it is used to effect actual hydrolysis of a complex. The hydrolysis may be effected in a jacketed hydrolyzing vessel provided with l a stirrer and sufficient hydrolyzing agent should be employed so that after subsequent separation the aqueous layer will contain at least one part oi' Water to six parts of HF and preferably about 1 part of water to 11/2 parts 0f HF.

The hydrolysis may be effected in a plurality of stages either with or without countercurrent contacting and preferably with cooling between stages. If sufficient intimacy of contact and adequate temperature control is provided the hydrolysis may be effected in a countercurrent tower. It is preferred that the temperature of hydrolysis be '1n the range of 30 to 200 F. during initial contacting. The hydrolyzed complex is thus substantially freed from HF, i. e. it contains less than about .2 to .3% HF by weight. Any residual HF is preferably removed from the hydrolyzed product by intimate contact with alkaline solution such as caustic ammonia, lime slurry, etc. The neutralized product may then be distilled with inert gas, steam or under vacuum to remove any low boiling components therefrom and to produce drying oils either as overheador as undistilled fractions of desired molecular weight. The drying oils thus produced have remarkably high iodine numbers which usually 500, they are usually characterized by 4 to 8 double bonds per molecule (about one pair in conjugated position) and they have surprisingly good color. A typical drying oil before distillation may have an average molecular weight of about 390, a Viscosity of Z-2 Gardner at 25 C., an iodine number of about 440, an ASTM color of about 6-'7 and a maleic anhydride value of about 165. In this connec- HF. One mol of double bonds as err- It should be noted tion, iodine number is understood to mean centi- ,vgrams'o'f iodine per gram of sample as determined by'the Wijs iodine monochloride procedure using 1/2 hour reaction time and 200% .f referred to as the diene number) and is a measure of the amount of conjugated olenic double bonds in the samples.

If the stripped complex is hydrolyzed with a .carefully controlled amount of hydrolyzing agent such that the final Weight ratio of HF to Water in the aqueous layer is above about 1.2 (55 parts HF and 45 parts of water) the separated olenic oil will be of considerably higher viscosity, (e. g. Z Gardner or higher) and will contain substantiallyA no low boiling compounds. If the final ratio of HF'to Water in the aqueous phase is lower' than about 0.8 (45 parts HF:55 parts water), the separated total olefinic oil after hydrolysis will be relatively non-viscous (e. g., less than L Gardner), and will contain 15-35% of low boiling fractions having a viscosity of less than A Gardner which are unsuitable for use as drying oils. If the stripped complex is hydrolyzed with an alkaline reagent such as ammonia or caustic solution, the separated total olerlnic oil will have a Gardner viscosity of less than A and will contain 254=5% of low boiling fractions.

The aqueous layer from the hydrolysis step which may now contain about 0.8 to 1.2 parts of HF per one part of Water by weight is subjected to a partial distillation step under conditions to remove substantially anhydrous HF overhead. However, if the rst hydrolyzing opration is conducted so that the Weight ratio of HF to water in the aqueous layer exceeds 1.2, said aqueous layer should be subjected to a second hydrolyzing step before distillation, in order to reduce the HF to water ratio in the aqueous layer to a value of 1.0-1.2. This is important since aqueous HF containing more than about 1.2 parts by weight of HF per part water will retain a considerable amount of olefnic oil in solution. The distillation of the aqueous HF solution is carefully controlled to distill substantially anhydrous' HF overhead, thereby leaving about 1 part of HF per 1.5 parts of water in the aqueous solution which is withdrawn from this operation and again utilized in the hydrolysis step. Thus in normal operation no water is added to the system and no aqueous HF has to be Withdrawn therefrom. The Water component simply goes round .and round in the hydrolyzing cycle and the HF removed from the complex is thus recovered in substantially anhydrous condition for reuse in the treating step.

The invention will be more clearly understood from the following detailed description read in conjunction with the accompanying drawings in which:

Figure 1 is a schematic flow diagram illustrating a commercial plant for practicing the invention, and

Figure 2 is a hydrolysis system utilizable in the system of Figure l.

Before describing the operation illustrated in the drawings, data will be presented to show the importance and significance of operating conditions. A preferred charging stock is dearomatized gas oil. The following table sets forth data obtained by treating various charging stocks with a 2:1 HF/oil weight ratio at a temperature of about 330 F. for a contact time of about 20 min- Qfl l 6 utes in an autoclave provided with a'motcr-driven -aromatiaation ibyrcpeated treatmentwth sulfuric kpropeller-type agitator. Irl-these runs, a't-the end acid. Emplbying the Vsaine treating lcolld'itions of the reaction period, the reaction mixture was (2:1 HF-oil weight ratio, 330 F. and 120 lminutes allowed to settle while cooling to .Vroom temperacontact time, .hydrolysis with aqueous ammonia) ture. The lower HF phase was then withdrawn 5 the followingcomparative data were obtained:

from the bomb through a Saran tube into a neutralizing mixture of aqueous ammonia and Vir Dearoen; cracked ice. The transparent Saran tubing om stock GasOllA 'ig served as a means of noting when the interface A between the acid and the hydrocarbon phases 1o mmaucs.-- 11.11 1 had been reached. The ammonium-:fluoride solu- "l'me Per .0011* CnvefSiOn 4M 59 Y`elds ol. Pci-2Com on CHG tion was allowed to settle andthe poly-Oleincoil :l v`Dr;(fVG s .4 .1.2 was decanted from the solution. The hydrocarggxflflfa-e 4.111. .12.8 bon phase from the reactor was neutralized in a jl similar fashion and collected separately. 2 15- g Elect of charge stocks 15'1 12'9 i i. i. L 22.11 34.1 C15 Cm l C15 C45 y@ g 59-'5' '4&7 Charge Stock Brauched Normal Branched; Normal 01811111 011111112' Para-dmv `1111111111111 1-9 .4-0 5.6 11.2 9.2 8.1 Vol. per cent Conver- Total- 16.1 23.3 Ylfessaiaoii 93311193 (2132i 2315. vi PropertiesofHF Soluble 011: Y

g 440 v467 503 475 I0iII8'N1mbBr"(WS,'$/ hr.) 297 475 edflatligendx 1 526 1 501 y1 502 1 49s spemcfvifyimF-J 9786 9059 tive-'Index (11 2.9--.. .1 -505 Molecular We1ght 212 205 213 25 gterviscosityatvc l A 4 Dcaromatized Gas Oils Approximately 6 centmokes' Charge stock C-TII The eiect .of aromatics on the nature and exmet11y1pe11ta11e Param 1 Napa tent of the-conversion is .strikingly illustrated in theme 30 the `above table. With respect to the HF-'soluble products, the pronounced diilerence in proporggggg lsggngfsfong Gg tions and lparticularly'in degree of unsaturation is Iodine sos 415 481 shown by .the following comparative data. on re- 1l Ivggggt-:nu: Mg .zog vspective 11F-soluble 'products after neutralization 5 to remove .nal traces of HF' and after Vremoving l Tetra isobutylenc fraction `recoveredfrom isobutylenc polymer C5 andiightefhydrocabons. produced by H2SO4 polymerization.

2 Normal-hexadecene, 957 purity. f 3 Product vfrom complete lodydrogenation of (1). HF Saluble 'products from 4 Cetane, 95% purity.

East Texas gas oil (400e650 F. boiling range dearomatlzcd by n v g gEagt'TexasGag Dearomatized exhaustive sulfuric acid treating to a reduced aromatic con't'exitcf 4" Oil Gas Oil less than 1%. Fraction-Approx. `Boiling Hastings gas oil (400-650 F. boiling range, dearoma'tized by exhaustive sulfuric acid treating to a reduced aromatic content of Per Iodine Per AIodine less than 1%. -Gent Number* Cent VNumber When consideration is given to percent `rconf version. unsaturated oil yield in conversioniprodfgl'gg a mm ucts and iodine number of unsaturated v011,111: will 154 2m`0 laj1mmj 27u 255 12 '445 be noted that the dearomatized gas oils Aprovide Bottoms (Tar) 58 "181 23 348 the best charging stocks particularly when 'their 'rom jou 10o 291 mo 415 cost is compared with that of other charging stocks. The effect of dearomatization `is shown A 'more detailed :analysis of the HF-soluble by comparative tests'on a virgin vEast Texasgas product lfrom the treating `of `virgin East Texas oil as compared with the same gas oil lafter degas oil 'is'as'followsz GASOLIN-E .RANGE MATERIAL GS 'O'HJRANGE MATERIAL 16.7 I 1 555. '336 `1.5125 :90216` 177 (16g) -136v l.I 620, 293. .1. 5350 .9382 197 l-HEAVIER 'THAN G. OnRANGE MATERIAL 6---.--- 10.3 21-1. y1 soo .213l 1-5183 f .9916-. y253 bonds per mol) which are For comparison,V properties of :the HF-soluble product obtained from they-HF treating ofdeto-fore obtainable from petroleum, but the striking diierence between such drying oil and the aromatized gas oil are as follows;

l i i one 'I toEisiim'ited I am 25 sp G w11 v em.a v emp. o e r. 1 o. CutNO- percent o. mmpng Ameomm. Number nu At25 o. wz.

on Chg. F

GAsoLINE RANGE MATERIAL 775 119 Y715 212 aa v1.51150 '.0815 102 GAS oIL RANGE MATERIAL 1 Gardner viscosity at 25 C.=A (ca. 50 cs or 230 SSU at 25 C.) l Gardner viscosity ot C.=L (012.300 cs or 1460 SSU at 25 C.)

lute and degrade the polyolen products and thereby decrease their value as drying oils.

In addition to the above properties o HF- soluble products produced from dearomatized gas oil it is noteworthy that such products possess la high maleic anhydride value (MAV). For example, cut No. 2 had an MAV of 625 which with its iodine number of 613, molecular weight of 132, andsrefractive index of 1.4665 indicates a mixture of tri and tetra olens (3.2 double largely conjugated in structure; i. e. at least 85% of the molecules have one pair of conjugated double bonds.

This was qualitatively confirmed by ultra violet spectrophotometric observation. A blend of cuts 4, 5 and 6 showed an MAV of 302, an iodine number of 475, a refractive index 011.517 and a molecular weight of 250; this indicates that the material is composed of polyolens containing approximately 4 or more double bonds per molecule and that about 75 to 80% of the material contains one pair of double bonds in conjugation. This is a very unusual combination of properties.

The colors of the vacuum distillate fractions were good varying fromy1-11/2 for the lower boiling components to 3%2-57ASTM for the high boiling products.

For use in the drying oil and/or resin field, cuts 4, 5 and 6 (which represent approximately 43% of the total HF-soluble product) possess the requisite low volatility and adequate body (viscosity) to meet commercial requirements. Each of these fractions air dry readily and a composite sampleproduced a iilmV corresponding to a polymer drying oil produced by contacting unrened cracked gasoline vapors with an y Such` clay polymer .i

dryingA oil of this invention is shown by the iollowing tabulated properties:

Drying oil from HF Drying Oil treating of from Clay dearom. Polymer gas oil 1 Boiling Range C. at 1 mm. Hg 10G-185 10i-225 .Refractive Index at 25 C l. 5178 1. 5365 Specific Dispersion (mmc) 1,' 170 Specic Gravity at 25 C.- 0A 9274 0.969 Iodine Number 439 189 M. A. V 302 27 Per CentConJugation (from M. A. V.) 77 7 Approximate Mol. Weight 250 290 Viscosity at F.:

Centistokes 17. 28 4l. 7 Saybolt Universal Sec 86 194 Color:

Gardner 13 15 AST 4+ 5 Drygtltmtxe: l1) H 2 154-254 e o ouc rs. 1 -21/ (Tack-freel-Hrs 6-8 b 6-8 1 Composite oi cuts 4, 5 and 6. l With 0.5% lead naphthenat-e and 0.05% cobalt naphthenate driers Referring now to the efEectj of process variables in producing the polyolen or drying oil materials, the most important are HF/oil ratio, contact time (assuming intimate mixing) and temperature. As the HF/oil weight ratio is increased from about .25:1 to about 3:1 there is a gradual increase in product iodine number and a substantial increase in yield. HF/oil ratios below about 1:1 are usually undesirable not only because of limited yield and lower product unsaturation but because of limited physical capacity of the available HF to dissolve the polyolenic material. The preferred HF/oil ratio is about 1:1 to 2:1 and it is usually uneconomical to employ a greater ratio than 5:1. The properties of the drying oil are not substantially affected by changes in the HF/oil ratio.

The required contact time is dependent on temperature and intimacy of contact; higher temperatures make possible the use of shorter contact times. With an HF/oil ratio of 2 (i. e. 2:1) and a 20 minute contact time, a yield of about 12% is obtained at 265 F. (iodine number 461) while a yield of about 22% is obtained at about 300 F. (iodine number about 510). Adequate conversion at lower temperatures may require a contact time of an hour or more. At temperatures of the order of 400 F. the contact time for equivalent conversion may be f the o'rder of about 3-5 minutes. Thus the time of contact may vary from about a minute to an hour or more depending upon the temperature employed but at preferred temperatures such contacting time is in the range of about 5 to 30 minutes, e. g. about 15 to 20 minutes. The preferred temperature is in the range of about 300 to 400 F. The iodine number has been observed to decrease with excessively long contact times, said decrease being accompanied by an increase in molecular weight and specc gravity.

It should be pointed out that in all' of the ,The desirability of leaving at least one and preferably one and lone half to two molecules of HF per double bond in the poly-olenio oil present in the partially stripped complex is thus demonstrated.

Using partially stripped complex containing approximately 40% HF, a series of experiments were yconducted in rwhich the stripped complex was hydrolyzed by slowly pouring the partially stripped complex into a Water cooled jacketed copper vessel equipped with an agitator and containing varying amounts of water. The following table shows the concentration of HF in the aqueous HF layer together with the properties of the recovered oils.

above examples, the HF phase from the treating step was withdrawn and hydrolyzed in aqueous ammonia containing cracked ice. The recovered olefinic oil is of relatively low vicosity and contains a substantial amount of relatively non-viscous light fractions. By effecting the hydrolysis under carefully controlled conditions with aqueous HF, the viscosity of the recovered oil is increased to an unusual degree and the proportion of low viscosity light fractions is reduced considerably or substantially eliminated.

Prior to hydrolysis, the HF phase is partially stripped to remove most of the HF from the HF complex. The importance of leaving at least one and preferably one and one half to two molecules of HF per double bond present in the oil is illustrated-by the following run made on HF phase material produced by HF treating of dearomatized naphthenic gas oil substantially as hereinabove described. The HF phase material was charged to a continuous type stripping co1- umn packed with carbon Raschig Rings. The stripping was conducted in countercurrent fashion at stripping rates equivalent in most cases to approximately 1 cubic foot of natural gas per liter of HF phase per minute. By varying the heat input to the nichrome wire wrapped in 'sections around the stripping tower, various degrees of removal of HF were attained as shown in the summary table below. The relationship between the iodine number of the stripped and recovered oil (after nal ammonia neutralization) and the HF content of the residual stripped oil (before neutralization) is especially noteworthy.

line I0 through heater II to reactor I2 together with HF introduced through line I3, about 2 parts by weight of HF in this case being introduced per part of oil charge. The reactor may be a batch type or continuous reactor of any known type which will give suiicient intimacy of contact for the required period of time and it is illustrated as a cylindrical vessel provided with a mechanical stirrer I4 driven by motor I5. In -the reactor conversion is effected at a temperature of about 330 F. with a contact time of about 20 minutes under a pressure suicient to maintain liquid phase conditions, e. g. about 800 to 1500 p. s. i. The charge should of course be dry when it is introduced into the system and conventional drying towers may be employed when necessary. The reactor and other elements must of course be fabricated from or lined with metals, alloys or compositions which are resistant to hydrogen fluoride corrosionand may for example be of Monel construction. The reactor may consist of a tank provided with a pump-circulated emulsion stream such as employed in conventional sulfuric acid alkylation operations. The intimate mixing in the reactor may be obtained by the use of rotating shear discs adjacent to stationary plates. Since no in- Composition ofsidual Stripped Approx. L No. of Run No. Stripping Neutral- Sp. Gr.

Temp. Weight Per Moles HF per ized O11 Per Cent Cent Mole of Double of HF Oil Bondsl 197 0.5 99.5 0.1 269 0. 9G42 10 90 0.33 340 0.9553 82 20.3 79.7v 0. 08 408 0.944 79 37.3v 62.7 1. 57 425 0.932 236 41.9 58.1 1.92 454 0.929 81 45.1 54.9 2.22 448 0.955 480 0.9 18

i il 'recovered byneutalizaton of total samp 1 calculated on ce bass 0141s nnb., 22511191.1979. and 4,2 Y(u1/:n.014 1n 31104535,

vention is claimed in the reactor per se it requires no further description.

The reaction mixture is passed through a. cooler I6 before being introduced from line I1 to product separator I8. The separator or settler I8 may :be operated at substantially reaction pressure but at a temperature below about 250 F. and preferably in the range of about 80 to 180 F. The insoluble saturated oil fraction ilows over bailie 19 and is withdrawn through line 20 to stripper 2I which is provided with conventional heating means 22 at its base. Substantially all of the HF is drawn overhead along with'light hydrocarbons through line 23 and cooler 24 to HF settler 25 which is preferably operated at a temperature obtainable with ordinary condenser water. Any condensed hydrocarbons separate out as an upper layer and they may flow over baiile 26 and be withdrawn through line 21. A

portion of such material may be employed as a stripping gas in stripper 2| and/or in the complex stripper which will be hereinafter described. The net production of the condensed hydrocarbons may be passed through a bauxite tower or otherwise treated to remove HF and/or combined iiuorides. Similarly the gas vented from the settler through line 28 may be freed of HF and utilized in any conventional manner. The acid layer is withdrawn through line 29 to HF storage tank 30 from which it is supplied to line I3 by pump 3 I.

The stripped saturated oil leaves the base of stripper 2l through line 32 and is then fractionated in a conventional system diagrammatically illustrated by tower 33, the light hydrocarbons such as gasoline being taken overhead through line 34 and thel heavier hydrocarbons being withdrawn through line 35.

The HF phase which may in this case consist of about l0 to 20 weight percent of unsaturated hydrocarbon material and 80 to 90% by weight hydrogen fluoride is withdrawn through line 3S to HF-complex stripper 31 to which a, stripping gas (e. g. from line 21) may be introduced through line 38. Heating means 39 may be employed at the base of this stripper but the temperature thereof should not exceed about 300 F. and preferably should be not higher than about 150 F. to 200 F. in order to avoid degradation of the HF-hydrocarbon complex. The stripping in tower 31 should be sufficient to remove the uncombined HF but to leave at least 1 molecule and preferably 11/2 to. 2 molecules HF per double :bond of olenic material contained in the HF solution. In other words, the HF content of the introduced mixture should be reduced to about to 50% by weight but should not be reduced to less than about 30 by weight.

The HF and stripping gas which leaves the top of stripper 31 through line 40 may be combined with the overhead from stripper 2 I; a part of the overhead may be introduced through branched line 4I into the upper part of stripper 2l and another part may :be introduced directly to line 23.

The 11F-unsaturated oil complex from the vbase of stripper 31 is introduced through cooler 42 and line 43 into a hydrolyzing system 44 which is shown as a continuous countercurrent tower in Figure 1 and as a multiple batch system in Figure 2. Hydrolysis is effected by means of an aqueous HF solution containing at least about l part HF to 2 parts water, said solution being introduced through line 45. The amount of HF solution inratio in the aqueous HF solution leaving by line 5I will be in the range of 1:1 (i. e. 5-0 weight percent HF) to 4:1 (i. e. 80 weight percent HF) if viscous products are desired; if nonviscous uid oils are desired, the iinal HF water ratio should be less than 1:1. In the system diagrammatically illustrated in Figure 1, hydrolysis is effected in a countercu'rrent tower which may be provided with suitable mixers or contacting surfaces and which may be provided with a series of cooling coils 46, 41 and 48 for temperature control. At the complex inlet end the temperature should be relatively low, e. g. about 35 to F. At the upper end of the hydrolyzing tower Where the complex has been substantially denuded of combined HF, a higher hydrolyzing temperature of the order of to 175 F. may be employed for removing as much as possible of the combined HF and to decrease the viscosity of the polyoleflnic oil so as to facilitate the separation ofV oil and aqueous phases. When produclng extremely viscous oil, it is advantageous to introduce a light hydrocarbon diluent stream, such as pentane, into tower 44 in order to facilitate the separation of the desired polyolenic oil. While the use of a countercurrent system with a temperature gradient as hereinabove described is preferred, it should be understood that the hydrolysis may be effected at a substantially constant temperature attainable by cooling water or refrigeration, i. e. in the range of 35 to 125 F. or about 60 F.

For obtaining a fractionation of the polyolenic oil components (i. e., a separation of the oil into components of higher and lower degrees of unsaturation and improved color) in the hydrolyzing step it may be desirable to employ one or more stirred batch-type hydrolyzers as illustrated in Figure 2. This may be accomplished by a stepwise addition of the hydrolyzing medium. Complex from line 43 and aqueous HF (approximately 1.6 parts water and 1 part HF) from line 45 are introduced into stirred mixing vessel 44a which is provided with a j acketed cooler 48a. The' amount of aqueous HF may be regulated to produce a concentrated HF layer containing about 3-6 parts of HF per part of water by weight. After intimate mixing for a. period of 2 to 20 minutes at about 35 to 150 F., an equal volume of pentane or other light hydrocarbon diluent is added and the mixture stirred for 5-10 minutes additional. The mixture is then introduced by line 49 into batch settler 511. After settling for about 2O minutes the concentrated aqueous HF solution is withdrawn from settler 50 through line 43a where it is mixed with an additional quantity of aqueous HF from line 4519. A pentane solution of an oil A, of comparatively low iodine number (e. g. about 250), is then removed through line Sla. amounting to about1020% of total oil contained in the complex. Oil A is nally recovered from the pentane solution by any conventional stripping method; color of the recovered oil A is about 5 ASTM. The concentrated HF solution previously removed from settler 50 and mixed with additional aqueous HF from line 45h is then introduced into mixing vessel 44h. After stirring for another 2 to 20 minutes in this mixer while maintaining a temperature of 35 to F., by cooling jacket 41h, an equal Volume of pentane is added and stirred as described above. The mixture may then be introduced by line 49 into settler 50' from which aqueous HF is withtroduced is controlled so that the final HF water 1:5

drawn through line 5 Iband a .pentane solution of crude higher iodine number drying oil B is withdrawnrthrough line 52. The aqueous layer with-- drawn from settler 50' should contain at least about 1 part of HF per part of water by weight and may for example contain 1.2-1.8 parts of HF per part of water. Depending on the nal aqueous HF concentration, r-90% of the remaining oil will be recovered in the second hydrolyzing step; thisoil has a color of 6-8 ASTM. The aqueous layer withdrawn from line 5Ib may be subjected to a third hydrolyzing operation or it may be sent to an HF distillation tower wherein HF is recovered.

Regardless of the particular type of hydrolysis system employed, the crude drying oil solution which leaves said system through line 52 will still contain a small amount of HF which is usually less than .3% and is preferably less than .1%. To remove nal traces of HF the crude drying oil solution may be contacted with bauxite but it is preferably neutralized with ammonia, lime slurry or a concentrated caustic solution introduced through line 53 and intimately mixed with the crude drying oil solution in mixer 54. The mixture then passes to settler 55 from which the caustic is settled out and withdrawn through line 56, most of the caustic being recycled by pump 51 and a very small amount of spent caustic being withdrawn through line 58.

The neutralized product may then be distilled under subatmospheric pressure after preliminary distillation for removal of pentane (preferably in the range of 1 to 10 mm.) in conventional distillation equipment illustrated by tower 60, the gasoline boiling range materials being taken overhead through line 6|, drying oil distillate being recovered through line 62 and a high boiling polyl oleinic drying oil or resin being withdrawn through line 63. Fractions of any desired boiling ranges may thus be obtained. Atmospheric ash distillation may be employed where the time at elevated temperatures is minimized. A preferred operation is atmospheric distillation in a rst tower to remove the solvent and the lowest boiling component followed by vacuum distillation in a second tower for separation of one or more drying oil fractions.

The aqueous liquid withdrawn from the hydrolyzing system may contain about to 80%, usually about to 65% by weight of HF, and such solution is withdrawn by line 5| (or Bla and 5|b) and introduced into HF fractionator 64 which is provided with a suitable heater 65 at its base and reux coil 65a at the top. This fractionator is carefully operated to distill overhead substantially anhydrous HF from a constant boiling mixture of about 1 part HF and about 1.6 parts water. At atmospheric pressure such distillation may be effected at a temperature of about 70 F. at the top of the tower and about 230 F. at the bottom of the tower. The anhydrous HF passes through line 66 and condenser \El to HF storage tank 30 at 20 pounds pressure, the temperature at the top of the tower will be about 110 F. with about 275 F. at the bottom. The constant boiling mixture, Which may be about 1 part HF and 1.6 parts water but which will vary slightly in composition depending on the pressure in tower 64, is returned by pump 68 and line 45 to the hydrolyzing system. Some oil may be associated with the constant boiling mixture from tower 64 and should be separated by decantation in a suitable settler.

In starting up the operation, the hydrolysis is effected by introducing water from line 69 into line 45 but once the required amount of water is introduced, it simply circulates around and 14- l. around between hydrolyzer M and HF fractionato'r 6,4, the water removing- HF from the complex in the hydrolyzer and HF 'being removed from the water in the HF fractionator. Ifv any additional water enters the system it will tend to build up in this cycle in which case dilute HF must be removed through line 10. Since the recovery of HF from"such a dilute solution is a difcult and expensive procedure it is important to avoid any such build-up and to employ charge materials which are substantially anhydrous. Generally speaking, the solution introduced from the HF fractionator to the hydrolyzer shouldv contain about 36 to 40 72,V HF and the solution returnedv from the hydrolyzer to the stripper should contain about 45 to 65% HF. It may however be possible to alter the amount of HF in the solution by employing water soluble additives such as HF salts.

From the description it will be seen that the objects of the invention have been attained. The invention is not limited, however, to the details hereinabove set forth since many modications of equipment and alternative procedures, conditions and proportions will be apparent from the above .description to those skilled in the art.

We claim:

1. The method of hydrolyzing an HF-polyoleiinic hydrocarbon complex wherein the polyolenic hydrocarbon component contains about 4 to 6 double bonds per molecule which method comprises initially contacting said complex with an aqueous HF solution containing at least about 50 but less than 80 Weight percent HF while removing heat of hydrolysis and electing said hydrolysis by initially contacting the complex with a portion of said solution at a temperature below about F. and contacting partially hydrolyzed complex with a portion of said solution at a higher temperature which is below 200 F.

2. The method of obtaining a viscous high molecular weight drying oil having a high iodine number from an HF-hydrocarbon complex obtained by treating a hydrocarbon oil which is substantially free from aromatic hydrocarbons with hydrogen fluoride at a conversion temperature not higher than 450 F. with an HF to oil ratio in the range 0f .2:1 to 5:1 and for a contact time sulcient to obtain substantial conversion followed by separation of an HF phase containing said complex dissolved in a large amount of free HF from a saturated oil phase containing a small amount of dissolved HF, which method comprises stripping said HF phase at a temperature in the range of about to 250 F. under conditions for removing substantially all free HF and for leaving complex which contains about 1 to 2 molecules of HF per double bond of the hydrocarbon component of the complex, hydrolyzing with an aqueous HF solution said complex which contains at least 30 weight per cent combined HF but not more than 50 weight per cent HF after the removal of free HF therefrom, initially contacting said complex in the hydrolyzing step with an aqueous HF solution which contains at least about 50 but less than 80 weight per cent HF. effecting at least the initial part of hydrolysis at a temperature in the range of 35 to 125 F. and eifecting all of the hydrolysis at a temperature below 200 F., separating aqueous HF from hydrolyzed complex, removing residual HF from said hydrolyzed complex to obtain HF-free hydrocarbons and .distilling said HF-free hydrocarbons at subatmospheric pressure.

3. The method of claim 2 which includes the 4. The method of claim`2 whieh includes the step of adding a. suiicently small amount of` aqueous HF so that the amount of HF in the aqueous HF composition after hydrolysis willbe in the range of 55 to 65 weight per cent.

5. The method of claim 2 wherein the hydrolyzng is accomplished by stepwise addition of said aqueous vHF solution and wherein a light hydrocarbon .diluent is added to the hydrolyzed mixture to facilitate phase separation.

ROBERT J. LEE. PAUL D. MAY.

The following references are of file of this patent:

16 REFERENCES c ITEn reod the UNITED STATES PATENT Number Name vDate Kuhn Feb. 24, 194s Bloch Apr. 27, 1948 Johnstone May 24, 1949 

1. THE METHOD OF HYDROLYZING AN HF-POLYOLEFINIC HYDROCARBON COMPLEX WHEREIN THE POLYOLEFINIC HYDROCARBON COMPONENT CONTAINS ABOUT 4 TO 6 DOUBLE BONDS PER MOLECULE WHICH METHOD COMPRISES INITIALLY CONTACTING SAID COMPLEX WITH AN AQUEOUS HF SOLUTION CONTAINING AT LEAST ABOUT 50 BUT LESS THAN 80 WEIGHT PERCENT HF WHILE REMOVING HEAT OF HYDROLYSIS AND EFFECTING SAID HYDROLYSIS BY INITIALLY CONTACTING THE COMPLEX WITH 